TimeStored Blog

kx kdb – 2018 in Review – Changes

kdb Version 3.6 Changes:

• Enums and linked columns now use 64 bit indices
  • This is a disk-format change, i.e. newly saved data will NOT be backwards compatible.
  • 3.6 will be able to read data in the old format
• AnyMap – Mapped Nested Types
  • Ability to save unmappable compound objects with >2 billion elements
  • Mapped list elements can be of any type and are data remains mapped NOT copied to heap.
    • Symbols are automatically enumerated against a file with three ###s in the name.
• Deferred Response – -30!x Allows a deferred response to a sync query. In practice it is difficult to use correctly.
• New Functions:
  • .Q.hg – HTTP get allows retrieving web page as a list of strings.
  • .Q.dtps/.Q.dpfts added to allow specifying the enum domain
  • .Q.sha1 – SHA-1 encode text
  • .Q.ts – Allows timing a function call similar to apply “.”.
  • xcol – Now supports dictionary to remap column names
  • -27! to allow formatting similar to .Q.d
  • .j.jd – Allows specifying dictionary of options when calling json serialization.
  • .Q.btoa – Base 64 encode
  • .Q.hp – HTTP Post – .Q.hp[url;mimeType;query]
• Performance Improvements on
  • grouping
  • filtering
  • particularly when attributes present
• SSL – Improvements and bugfixes
• WebSockets – Improvements and bugfixes